How does bolt tensioning work?

Bolt tensioning works by preloading the bolt, stretching it before the nut is tightened. The tensioner is clamped to the bolt’s threads and pushes against the flange in the surface being bolted. This provides a very consistent amount of stretch to the bolt, ensuring consistent bolt stretch and clamping force.

What is a hydraulic bolt tensioner?

A hydraulic bolt tensioner is an annular jack which fits over the bolt and nut to be tightened. Bolt tensioning tools can be grouped together to enable multiple bolts to be tightened simultaneously to the same high and accurate pre-load.

What is a tensioning nut?

Tension is the stretch or elongation of a bolt that provides the clamping force of a joint. A bolt and nut are designed to act together as the internal threaded fastener (nut) is tightened onto the externally threaded fastener (bolt). It stretches the bolt and when the nut is applied, creates consistent clamping force.

What is the difference between bolt torquing and bolt tensioning?

Bolt torque and bolt tensioning are both legitimate ways to seal a joint. Bolt torquing exerts a rotational force on the fastener, while bolt tensioning involves stretching a fastener with what looks like a hydraulic load cell.

Why do you need to torque bolts?

In simple terms, you need torque to create tension in a bolt. You use torque to turn a nut onto a bolt and then to stretch the bolt, making it a solid spring that clamps the two materials together.

How does a hydraulic tensioner work?

A hydraulic tensioner system consists of a hydraulic actuator in combination with a tensioner pulley. High dynamic belt loads are controlled by hydraulic damping. This damping is created when engine loads force the piston rod to move inwards displacing the oil in the cylinder.

What tools are needed for nuts and bolts?

Wrenches are used to tighten and loosen fasteners, mainly nuts and bolts. Wrenches are generally made from a chrome-plated steel alloy. The material makes wrenches both durable and simple to clean.

How do you calculate bolt tension?

The tensile load a fastener can withstand is determined by the formula P = St x As. To find the tensile strength of a particular bolt, you will need to refer to Mechanical Properties of Externally Threaded Fasteners chart in the Fastenal Technical Reference Guide.

What happens to a bolt when torquing?

When using a traditional wrench to tighten a bolt, the torque applied to the nut causes it to slide up the inclined plane of the threads. This dimension is the grip length of the bolted joint.

What is torquing and tensioning?

A hydraulically powered torque wrench uses high-pressure hydraulic power supplied from an air, battery, or electric-driven pump. The higher the pressure, the greater the amount of torque applied to the bolt. The unit of measure for torque is usually expressed in Ft. lbs or Nm.